Rating:
In this challenge we are given gmail screenshot. And its content is encrypted with caesar cipher.
To convert image to text we can use any OCR tool (I used this website - https://onlineocr.net/).
For better result we can cut the [image](https://github.com/BOAKGP/CTF-Writeups/blob/master/Google%20CTF%202018%20Quals%20Beginners%20Quest/OCR%20is%20cool!/data.png). Now we need to decrypt it. We don't know the key, but there are only 25 possible rotations, so we can try them all.
[This website](https://www.mobilefish.com/services/rot13/rot13.php) allows us to try all keys at once. We can see that ROT-7 looks like valid english text and there's also our flag.
[decrypted](https://github.com/BOAKGP/CTF-Writeups/blob/master/Google%20CTF%202018%20Quals%20Beginners%20Quest/OCR%20is%20cool!/rot7.txt)
Flag: `CTF{caesarcipherisasubstitutioncipher}`
